How to allign brackets with the text?

Question

I want to write Z[x] with those brackets alligned with the Z. I've tried using \lbrack and \rbrack but the result is basically the same, so what's the best way to force it to stay on the same line?

Answer 1

Welcome to TeX.SX! It seems to me this is a matter of font choice. That said, here is a way to align the “bottom” of brackets with the base line without changing fonts:

\documentclass{article}
\usepackage{graphicx}

\makeatletter
\newcommand*{\raisedChar}[1]{%
  \setbox\z@=\hbox{#1}%
  \leavevmode
  \raise\dp\z@\box\z@
}

\newcommand*{\@TextOrMathOpening}[1]{%
  \TextOrMath{#1}{\mathopen{#1}}%
}

\newcommand*{\@TextOrMathClosing}[1]{%
  \TextOrMath{#1}{\mathclose{#1}}%
}

\newcommand*{\raisedOpeningBracket}{%
  \@TextOrMathOpening{\raisedChar{[}}%
}

\newcommand*{\raisedClosingBracket}{%
  \@TextOrMathClosing{\raisedChar{]}}%
}

\newlength{\widthOfOpeningBracket}
\newlength{\widthOfClosingBracket}
\newlength{\heightOfZ}
\settowidth{\widthOfOpeningBracket}{[}
\settowidth{\widthOfClosingBracket}{]}
\settoheight{\heightOfZ}{Z}

\newcommand*{\scaledAndRaisedOpeningBracket}{%
  \@TextOrMathOpening{%
    \resizebox{\widthOfOpeningBracket}{\heightOfZ}{\raisedChar{[}}%
  }%
}

\newcommand*{\scaledAndRaisedClosingBracket}{%
  \@TextOrMathClosing{%
    \resizebox{\widthOfClosingBracket}{\heightOfZ}{\raisedChar{]}}%
  }%
}
\makeatother

% Abbreviations
\let\OB\raisedOpeningBracket
\let\CB\raisedClosingBracket
\let\sOB\scaledAndRaisedOpeningBracket
\let\sCB\scaledAndRaisedClosingBracket

\begin{document}
Z[x]\quad $Z[x]$
\medskip

Z\OB x\CB\quad $Z\OB x \CB$
\medskip

Z\sOB x\sCB\quad $Z\sOB x \sCB$
\end{document}

It feels a bit hackish, though. I don't propose making [ and ] active characters, as that would break too many things, but you could choose a pair of Unicode characters and proceed with either \newunicodechar as in this message or with \DeclareUnicodeCharacter as in that message.